A379040 - OEIS

%I #13 Dec 30 2024 16:07:51

%S 0,1,5,9,13,17,21,33,45,57,65,73,85,93,129,165,173,189,205,217,241,

%T 257,273,297,309,325,341,381,441,513,585,645,685,733,765,797,845,857,

%U 889,921,945,993,1025,1057,1105,1129,1161,1193,1205,1253,1285,1317,1365,1389

%N Fixed points in A379015.

%C Such points exist when the non-adjacent form representation of n is palindromic.

%H Wikipedia, <a href="https://en.m.wikipedia.org/wiki/Non-adjacent_form">Non-adjacent form</a>.

%o (Python)

%o def isok(n):

%o     E, r = n, 0

%o     while E:

%o         if E & 1:

%o             Zi = 2 - (E & 3)

%o             E -= Zi

%o             r += Zi

%o         E >>= 1

%o         r <<= 1

%o     return (r >> 1) == n

%o print([n for n in range(0,1400) if isok(n)])

%Y Cf. A379015.

%K nonn,base

%O 1,3

%A _Darío Clavijo_, Dec 14 2024

%E Leading 0 added by _Rémy Sigrist_, Dec 28 2024